You can describe your resources and filter the results based on the tags. To filter by tag:
Enter the following command and parameter:
euca-describe-tags --filter resource-type=[resource_type]
The following example describes all your tags.
euca-describe-tags
TAG emi-1A2B3C4D image appserver
TAG emi-1A2B3C4D image stack dev
TAG i-5F4E3D2A instance appserver
TAG i-5F4E3D2A instance stack dev
TAG i-12345678 instance database_server
TAG i-12345678 instance stack test
The following example describes the tags for a resource with ID emi-1A2B3C4D.
euca-describe-tags --filter "resource-id=emi-1A2B3C4D"
TAG emi-1A2B3C4D image appserver
TAG emi-1A2B3C4D image stack dev
The following example describes the tags for all your instances.
euca-describe-tags --filter "resource-type=instance"
TAG i-5F4E3D2A instance appserver
TAG i-5F4E3D2A instance stack dev
TAG i-12345678 instance database_server
TAG i-12345678 instance stack test